House



H. H. WESTINGHOUSE.

PISTON VALVE;

(No Model.)

Patented Aug. 5, 1884.v

UNITE STATES Pari-:Nii rrics H. HERMAN XVESTINGHOUQE, OF PITTSBURG, PENNSYLYANIA, ASSIGNOR TO THE NVESTINGHOUSE MACHINE COMPANY, OF SAME PLACE.

PISTON-VAhVE.` f

SPECIPICA'I'IQN forming part of Letters Patent No. 303,084, dated August 5, 1884.

Application filed April 10, 1884.

ra aZZ whcm it may concern:

Be it known that I, H. HERMAN Wnsrnenousu, a'citizen of the United States, residing at Pittsburg, in the county of Alleghenyv and State of Pennsylvania, have invented or discovered certain new and useful Improvements in Piston-Valves, of which improvements the following is a specifioation.

In the accompanying drawings, which make part of this specification, Figure 1 is a Vertical longitudinal central section through a piston-valve enbodying my invention; Fig. 2, a transverse section through the same at the line w w of -Fig. 1; Fig. 3, a longitudinal section, on an enlarged scale, through a portion of the Valve; and Fig. 4.-, a view in perspective of one of the packing-rings detached.

My invention relates more particularly to main ordistribution` valves for steam-engines of the class in which steam is adnritted to a Valve-chest between apair of pistons located upon opposite ends of a hollow body or sleeve, and is exhausted through said body, as in the engine described and shown in Letters Patent of the United States No. 2-10, 482, granted and issued to me under date of April 19, 1881.

The object of my present invention is to effectively prevent-leakage between a piston- Valve of such character and its chest or casing without inducing undue `friotion or wear, and the improvements claimed are hereinafter fully set forth.

In the practice of my invention the Valve proper is, as heretofore, composed of a hollow body or sleeve, 12, and a pair of hollow pistons, 38 39, formed on or Secured to the ends of the body, each of said pistons being connected by radial arnis to a central hub or boss, 15, by which the Valve is Secured to a sten, by which it is reciprocated within a casing, 40, communioating by openings 11 between the end pistons, with the steam-supply pipe, and by openings 13 14, which are alternately covered and uncovered by said pistons, with induction and eduction passages leading into opposite ends of the cylinder of a double-acting engine, or into adjacent ends of two double-acting cylinders, as the case may be, the exhaust of said cylinder being effected from the open- (No model.)

' gree of tightness -of the packing-rngs. 41 is assured by forming circumferential grooves 42 in the pistons 38 and 39 on the stean side of each packing-ring 41, so as to expose a portion of one of the sides of each ring` to the pressure of the stean in the Valve casing or chest, and placing the opposite sides of the rings in communication with the exhaustpassage through the center of the Valve, such communication being effected by forning a channel, 43, on the exhaust side of each ring, above one or more openings, 4-1, leading through the metal of the piston from the adjacent seat of the ring to the inside of the piston, as-shown in Figs. 1 and 3. The rings are thus held to their seats by the pressure of the stean upon an area equal to that of the channels 43, and c'onsequently move with the Valve as if made solid therewith, without tendenoy to release or relief by suo-h movement of their outward beari ng upon the linin 40 of the valvo-chamber. The rings 41 should be fiXed as against rotation upon their pistons, to prevent stean blowing through their joints into the openings 44, by dowel-pns 45, or in any other suitable manner.

*In an application for Letters Patent filed by me February 16, 1884:, Serial No. 120,690, I

have illustrated the employment of my improvenents as above described in a doublecylnder single-acting steani-engine, and it will be obvious that they may, without change of principle, be sinilarly applied in engines of 5 v 1. The combination, substantially as set forth, of a main or distribution Valve coniposed of two hoilow pistons connected by a tubiilar body, and packing-rings sprung into peripheral recesses in the pstons, each of said rings having a groove on one side fitting against a seat Which coininunicates by a passage with the interor or eXhaust side of the Valve, and being eXposed on its opposite side by a circular 'eoess cut in the Valve to the pressure on the steani side thereof.

2. The combination, suhstantially as set foi'tli, of a hollow piston-valve having circuin- 

